CyberKnife based fractionated stereotactic radiotherapy as an upfront treatment for cerebral arteriovenous malformation.

Background: To explore the therapeutic outcomes of CyberKnife based fractionated stereotactic radiotherapy (CKFRT) for patients with cerebral arteriovenous malformations (AVM).

Methods: Between January 2008 and October 2020, 45 patients underwent CKFRT for cerebral AVMs as a first treatment. The delineation of AVM targets included AVM nidus. The mean target volume was 4.07 cm3, and 9 lesions (20%) were larger than 10.0 cm3. The mean marginal dose was 24 Gy (range, 20-35 Gy). CKFRT was delivered in median 3 fractions (range, 2 ∼ 5 fractions). AVM obliteration following CKFRT was confirmed by magnetic resonance imaging or angiography.

Results: During a median follow-up of 47 (5-148) months, complete obliteration and partial obliteration of AVM after CKFRT were obtained in 23 (51%) and 13 (29%) patients, respectively. Median time to complete obliteration was 39 (15-63) months. The cumulative probability of complete obliteration rate at 3 years was 47%. Complete obliteration rate of AVM was associated with Radiosurgery-based AVM score, which was consisted of AVM volume, patients age, and AVM location. One (2%) patient had hemorrhage during the follow-up period.

Conclusions: CKFRT is an effective primary treatment for patients with cerebral AVMs with a low hemorrhage risk.